Dual-output LED power supply circuit with PWM dimming

Abstract

The utility model relates to the technical field of power supplies, and discloses a dual-output LED power supply circuit with PWM dimming, which comprises an EMC filter circuit, a PFC circuit, a flyback circuit, an auxiliary power supply circuit, a PWM dimming circuit and a power supply output circuit, the power supply input end of the EMC filter circuit is connected with an external AC power supply, the output end of the EMC filter circuit is connected with the input end of the PFC circuit, and the power supply output circuit is connected with the input end of the flyback circuit. The output end of the PFC circuit is respectively connected with the input end of the flyback circuit and the input end of the auxiliary power supply circuit, the output end of the flyback circuit is connected with the input end of the power supply output circuit, the output end of the auxiliary power supply circuit is connected with the input end of the PWM dimming circuit, and the signal end of the flyback circuit is connected with the signal end of the PWM dimming circuit. According to the LED power supply circuit, effective filtering can be realized, stroboflash cannot be generated to a post-stage, and PWM dimming can be realized, so that complete turn-off, 0-100% stepless dimming and the like can be realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to power supply technology field, concretely relates to a kind of LED power supply circuit of double-way output with PWM dimming. BACKGROUND

[0002] LED power supply is a kind of device to provide power to LED equipment, also known as power supply. Its main function is to convert AC into DC to meet the needs of LED lamp beads. The core features of LED power supply include high reliability, high efficiency and constant current output, which make LED power supply outstanding in energy saving and stability. Its function is: LED power supply converts AC into DC through transformer and rectifier, and provides for LED lamp beads. Since LED lamp beads can only be driven by DC, LED power supply plays a key role in converting between mains and LED. The input of LED power supply can be high-voltage power frequency AC, low-voltage DC, high-voltage DC, etc., and the output is a constant current source to drive LED to emit light.

[0003] The current market products generally use CBB capacitor filtering method behind the rectifier bridge, which will bring 100Hz power frequency ripple to the later stage, thus generating a larger ripple to the later stage, thus forming LED flicker. In order to improve this situation, we have developed a product through long-term research and design, which uses PFC power factor correction for input, thus improving PF value without causing flicker to the later stage; At the same time, control signal and PWM dimming signal are added to the output, which can realize complete shutdown and 0-100% stepless dimming.

[0004] Therefore, in view of the above problems, the existing power supply technology needs to be further improved. INVENTION CONTENTS

[0005] The utility model aims at overcoming the problem of power frequency ripple of existing power supply technology affecting LED flicker. Through rational design of power supply technology, EMC filter circuit, PFC circuit, flyback circuit, auxiliary power supply circuit, PWM dimming circuit and power output circuit are adopted, which can realize effective filtering without causing flicker to the later stage, and also realize PWM dimming to achieve complete shutdown and 0-100% stepless dimming.

[0006] The technical scheme of the utility model is as follows:

[0007] The application discloses a double-way output LED power supply circuit with PWM dimming, which comprises an EMC filter circuit, a PFC circuit, a flyback circuit, an auxiliary power supply circuit, a PWM dimming circuit and a power output circuit, wherein the power input end of the EMC filter circuit is connected with an external AC power supply, the output end of the EMC filter circuit is connected with the input end of the PFC circuit, the output end of the PFC circuit is respectively connected with the input end of the flyback circuit and the input end of the auxiliary power supply circuit, the output end of the flyback circuit is connected with the input end of the power output circuit, the output end of the auxiliary power supply circuit is connected with the input end of the PWM dimming circuit, and the signal end of the flyback circuit is connected with the signal end of the PWM dimming circuit.

[0008] The PFC circuit comprises a PFC input circuit and a PFC control circuit, the input end of the PFC input circuit is connected with the output end of the EMC filter circuit, the output end of the PFC input circuit is connected with the input end of the PFC control circuit, and the signal end of the PFC control circuit is connected with the signal end of the PFC input circuit.

[0009] The PFC control circuit comprises a chip U1, a diode D7, a capacitor C11, a capacitor C14, a capacitor C15, a resistor R33, a capacitor C9, a capacitor C13 and a resistor R29, the "1" terminal of the chip U1 is connected with one end of the resistor R29 and one end of the capacitor C13, the other end of the resistor R29 and the other end of the capacitor C13 are connected with the ground, the "2" terminal of the chip U1 is connected with one end of the capacitor C15 and one end of the capacitor C14, the other end of the capacitor C15 is connected with one end of the resistor R33, the other end of the resistor R33 and the other end of the capacitor C14 are connected with the ground, the "4" terminal of the chip U1 is connected with one end of the capacitor C9, the other end of the capacitor C9 and the "6" terminal of the chip U1 are connected with the ground, the "5" terminal of the chip U1 is connected with the output end of the PFC input circuit, the "7" terminal of the chip U1 is connected with the signal end of the PFC input circuit, the "8" terminal of the chip U1 is connected with the negative electrode of the diode D7 and one end of the capacitor C11, the positive electrode of the diode D7 is connected with the positive electrode of an external DC power supply, and the other end of the capacitor C11 is connected with the ground.

[0010] Further, the PFC input circuit comprises an inductor L1, a resistor R61, a transformer T2, a resistor R12, a diode D2, a capacitor C2, a diode D3, an NMOS Q1, a capacitor C7, a diode D4, a resistor R13, a resistor R17, a resistor R62, a resistor R21, resistors Rs0, Rs1, Rs2, a resistor R6, a resistor R16, a resistor R28, a capacitor C5 and a resistor Rs3, one end of the inductor L1 and one end of the resistor R61 are connected to the output end of the EMC filter circuit, the other end of the inductor L1 and the other end of the resistor R61 are connected to one end of the capacitor C5, the positive electrode of the diode D2 and the "4" terminal of the transformer T2, the negative electrode of the diode D2 is connected to one end of the capacitor C2, the negative electrode of the diode D3, one end of the resistor R6 and the input end of the flyback circuit and the input end of the auxiliary power supply circuit, the other end of the capacitor C2 and the positive electrode of the diode D3 are connected to the "2" terminal of the transformer T2, one end of the capacitor C7 and the drain of the NMOS Q1, the other end of the capacitor C7 is connected to the source of the NMOS Q1 and one end of the resistor R21 and the parallel resistors Rs0 / Rs1 / Rs2 / Rs3, the other end of the parallel resistors Rs0 / Rs1 / Rs2 / Rs3 is grounded, the other end of the resistor R21 is connected to the "4" terminal of the chip U1, the other end of the resistor R6 is connected in series with the resistor R16 and the resistor R28, the other end of the resistor R28 is connected to one end of the capacitor C13, the gate of the NMOS Q1 is connected to the positive electrode of the diode D4, one end of the resistor R62 and one end of the resistor R13, the other end of the resistor R13 is connected to the negative electrode of the diode D4 and one end of the resistor R17, the other end of the resistor R17 is connected to the "7" terminal of the chip U1, the other end of the resistor R62 is grounded, the other end of the capacitor C5 is grounded, the "12" terminal of the transformer T2 is grounded, the "11" terminal of the transformer T2 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to the "5" terminal of the chip U1.

[0011] Further, the EMC filter circuit comprises a fuse F1, a thermistor NTC1, a voltage-dependent resistor RV1, a mutual inductor LF1, a resistor R19, a resistor R20, a resistor R22, a resistor R23, a capacitor CX1, a mutual inductor FL2 and a bridge DB1, one end of the fuse F1 is connected to the live wire, the other end of the fuse F1 is connected to one end of the voltage-dependent resistor RV1 and a "1" terminal of the mutual inductor LF1, the other end of the voltage-dependent resistor RV1 is connected to one end of the thermistor NTC1 and a "4" terminal of the mutual inductor LF1, the other end of the thermistor NTC1 is connected to the zero line, a "2" terminal of the mutual inductor LF1 is connected to one end of a parallel resistor R22 / R20, one end of the capacitor CX1 and a "4" terminal of the mutual inductor FL2, a "3" terminal of the mutual inductor LF1 is connected to one end of a parallel resistor R23 / R19, the other end of the capacitor CX1 and a "1" terminal of the mutual inductor FL2, the other end of the parallel resistor R23 / R19 is connected to the other end of the parallel resistor R22 / R20, a "3" terminal of the mutual inductor FL2 is connected to a "2" terminal of the bridge DB1, a "2" terminal of the mutual inductor FL2 is connected to a "3" terminal of the bridge DB1, a "1" terminal of the bridge DB1 is grounded, and a "4" terminal of the bridge DB1 is connected to the input end of the PFC circuit.

[0012] Further, the flyback circuit comprises a flyback conversion circuit and a flyback control circuit, the input end of the flyback conversion circuit is connected to the output end of the PFC circuit, the input end of the flyback control circuit is connected to the output end of the flyback conversion circuit, the output end of the flyback conversion circuit is connected to the input end of the power output circuit, and the signal end of the flyback control circuit is connected to the signal end of the PWM dimming circuit.

[0013] Further, the flyback control circuit comprises a chip U2, a diode D6, a resistor R25, a resistor R26, a capacitor C10, a resistor R31, a resistor R34, a capacitor C16, a voltage stabilizing tube ZD1, a resistor R35, a resistor R27, a resistor R24, a diode D8, a resistor R63, a resistor R36, resistors Rs4, Rs5, Rs6, Rs7, a resistor R30, an NMOS tube Q2, a capacitor C12, a resistor R64, a diode D15, a resistor R15, a resistor R14, a resistor R18 and a capacitor C8, the "1" terminal of the chip U2 is connected with the signal terminal of the PWM dimming circuit, the negative electrode of the voltage stabilizing tube ZD1 and one end of the resistor R26, the positive electrode of the voltage stabilizing tube ZD1 is grounded, the other end of the resistor R26 is connected with the "8" terminal of the chip U2, the "2" terminal of the chip U2 is connected with one end of the resistor R25, one end of the resistor R31 and one end of the resistor R34, the other end of the resistor R34 is grounded, the other end of the resistor R31 is connected with one end of the capacitor C16 and the "4" terminal of the chip U2, the other end of the capacitor C16 is grounded, the other end of the resistor R25 is connected with the negative electrode of the diode D6 and the "8" terminal of the chip U2, the "5" terminal of the chip U2 is grounded, the "6" terminal of the chip U2 is connected with one end of the parallel resistor R35 / R36 and one end of the resistor R30, the other end of the parallel resistor R35 / R36 and the other end of the parallel resistor Rs4 / Rs5 / Rs6 / Rs7 are grounded in common, the "7" terminal of the chip U2 is connected with one end of the resistor R27, the other end of the resistor R27 is connected with the negative electrode of the diode D8 and one end of the resistor R24, the positive electrode of the diode D8 and the other end of the resistor R24 are connected with one end of the resistor R63 and the gate of the NMOS tube Q2 in common, the other end of the resistor R63 is grounded, the source of the NMOS tube Q2 is connected with the other end of the resistor R30 and one end of the capacitor C12, the drain of the NMOS tube Q2 is connected with the other end of the capacitor C12 and the flyback conversion circuit, the "3" terminal of the chip U2 is connected with one end of the capacitor C8, one end of the resistor R18, one end of the resistor R14 and one end of the resistor R15, the other end of the capacitor C8, the other end of the resistor R18 and the other end of the resistor R14 are grounded in common, the other end of the resistor R15 is connected with the output terminal of the flyback conversion circuit and one end of the resistor R64, the other end of the resistor R64 is connected with the positive electrode of the diode D15, the negative electrode of the diode D15 is connected with the direct current power supply, and the positive electrode of the diode D6 is connected with the direct current power supply.

[0014] Further, the flyback conversion circuit comprises a transformer T1, a capacitor C3, a capacitor EC1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a capacitor C1, a diode D5-1 and a diode D5, one end of the capacitor C3 is connected to one end of the capacitor EC1, one end of the parallel resistor R1 / R2 / R3 / R4, one end of the capacitor C1 and the "3" terminal of the transformer T1, the other end of the capacitor C3 and the other end of the capacitor EC1 are grounded in common, the other end of the parallel resistor R1 / R2 / R3 / R4 is connected to the other end of the capacitor C1 and one end of the parallel resistor R9 / R10 / R11, the other end of the parallel resistor R9 / R10 / R11 is connected to the negative electrode of the diode D5-1 and the negative electrode of the diode D5, the positive electrode of the diode D5-1 and the positive electrode of the diode D5 are connected to the "1" terminal of the transformer T1 and the drain electrode of the NMOS tube Q2.

[0015] Further, the power supply output circuit comprises a voltage stabilizing tube D1, a capacitor C6, a resistor R5, a resistor R8, a capacitor CE1, a capacitor CE2, a resistor R7 and a mutual inductor LF3, the positive electrode of the voltage stabilizing tube D1 is connected to one end of the capacitor C6 and the output end of the flyback circuit, the other end of the capacitor C6 is connected to one end of the parallel resistor R5 / R8, the other end of the parallel resistor R5 / R8 is connected to the negative electrode of the diode D1, one end of the parallel capacitor CE1 / CE2, one end of the resistor R7 and the "3" terminal of the mutual inductor LF3, the other end of the parallel capacitor CE1 / CE2, the other end of the resistor R7 and the "2" terminal of the mutual inductor LF3 are grounded in common, the "4" terminal of the mutual inductor LF3 is used as the positive output electrode, and the "1" terminal of the mutual inductor LF3 is used as the negative output electrode.

[0016] Further, the auxiliary power supply circuit comprises an auxiliary circuit and an auxiliary control circuit, the input end of the auxiliary circuit is connected to the output end of the PFC circuit, the control end of the auxiliary circuit is connected to the control end of the auxiliary control circuit, and the output end of the auxiliary control circuit is connected to the input end of the PWM dimming circuit.

[0017] Further, the auxiliary circuit comprises a chip U5, a resistor R40, a resistor R44, a resistor R50, a capacitor CE6, a capacitor C20, a resistor R57, a resistor R56, a resistor R37, a resistor R38, a capacitor C17, a resistor R43, a diode D11, a diode D13, a resistor R47, a resistor R55, a resistor R45, a transformer T3, a capacitor C18, a resistor R42, a capacitor CE3, an optocoupler U6, a resistor R46, a resistor R52, a resistor R48, a capacitor C19, a resistor R53, a voltage regulator U7, a resistor R59 and a resistor R60, the "1" terminal of the chip U5 is connected with one end of the capacitor CE6, one end of the resistor R50 and the negative electrode of the diode D13, the other end of the capacitor CE6 is grounded, the "2" terminal of the chip U5 is connected with one end of the capacitor C20 and the "1" terminal of the optocoupler U6, the other end of the capacitor C20 is grounded, the "3" terminal of the chip U5 is connected with one end of the resistor R55 and one end of the resistor R47, the other end of the resistor R55 is grounded, the other end of the resistor R47 is connected with the "2" terminal of the transformer T3 and one end of the resistor R45, the other end of the resistor R45 is connected with the positive electrode of the diode D13, the "1" terminal of the transformer T3 is grounded, the "4" terminal of the chip U5 is connected with one end of the parallel resistor R57 / R56, the other end of the parallel resistor R57 / R56 is grounded, the "5" terminal of the chip U5 is connected with the "6" terminal of the chip U5, the positive electrode of the diode D11 and the "3" terminal of the transformer T3, the negative electrode of the diode D11 is connected with one end of the resistor R43, the other end of the resistor R43 is connected with one end of the capacitor C17, one end of the resistor R38 and one end of the resistor R37, the other end of the capacitor C17, the other end of the resistor R38, the other end of the resistor R37 and the "5" terminal of the transformer T3 are connected with one end of the resistor R40 and the output terminal of the PFC circuit, the other end of the resistor R40 is connected with one end of the resistor R44, the other end of the resistor R44 is connected with the other end of the resistor R50, the "8" terminal of the chip U5 is grounded, the "6" terminal and the "7" terminal of the transformer are connected with the positive electrode of the diode D10 and one end of the capacitor C18, the other end of the capacitor C18 is connected with one end of the resistor R42, the other end of the resistor R42 is connected with the negative electrode of the diode D10, the other end of the resistor R42, one end of the resistor R46, one end of the resistor R48, one end of the capacitor CE3 and the positive electrode of the DC power supply, the other end of the capacitor CE3 is grounded, the "9" terminal and the "10" terminal of the transformer T3 are grounded, the other end of the resistor R46 is connected with one end of the resistor R52 and the "3" terminal of the optocoupler U6, the "2" terminal of the optocoupler U6 is grounded, the "4" terminal of the optocoupler U6 is connected with the other end of the resistor R52, one end of the capacitor C19 and the negative electrode of the voltage regulator U7, the positive electrode of the voltage regulator U7 is grounded, the third terminal of the voltage regulator U7 is connected with one end of the parallel resistor R59 / R60, one end of the resistor R53 and the other end of the resistor R48, the other end of the resistor R53 is connected with the other end of the capacitor C19, the other end of the parallel resistor R59 / R60 is grounded.

[0018] Further, the auxiliary control circuit comprises an NPN tube Q4, a capacitor CE4, a Zener tube ZD2, a resistor R51, a resistor R49, a PNP tube Q5, a resistor R54, a resistor R58, a capacitor CE5 and a diode D14, one end of the capacitor CE4 is connected with a direct current power supply and an emitter of the NPN tube Q4, a base of the NPN tube Q4 is connected with a negative electrode of the Zener tube ZD2 and one end of the resistor R51, a positive electrode of the Zener tube ZD2 is grounded, the other end of the capacitor CE4 is grounded, the other end of the resistor R51 is connected with one end of the resistor R49 and a collector of the NPN tube Q4, the other end of the resistor R49 is connected with an emitter of the PNP tube Q5, a base of the PNP tube Q5 is connected with one end of the resistor R54 and one end of the resistor R58, the other end of the resistor R58 is connected with an input end of the PWM dimming circuit, a collector of the PNP tube Q5 is connected with the other end of the resistor R54, one end of the capacitor CE5 and a negative electrode of the diode D14, the other end of the capacitor CE5 is grounded, and a positive electrode of the diode D14 is connected with the direct current power supply.

[0019] Further, the PWM dimming circuit comprises an optical coupler U3, a resistor R32, a diode D9, an NPN tube Q3, a resistor R39, an optical coupler U4, a resistor R41 and a diode D12, a "1" terminal of the optical coupler U3 is connected with an output end of the auxiliary power supply circuit, a "2" terminal of the optical coupler U3 is grounded, a "3" terminal of the optical coupler U3 is connected with one end of the resistor R32, the other end of the resistor R32 is connected with a negative electrode of the diode D9, a "4" terminal of the optical coupler U3 and a positive electrode of the diode D9 are grounded, a "1" terminal of the optical coupler U4 is connected with one end of the resistor R39 and a base of the NPN tube Q3, the other end of the resistor R39 is connected with a direct current power supply, a collector of the NPN tube Q3 is connected with a signal end of the flyback circuit, a "2" terminal of the optical coupler U4 and an emitter of the NPN tube Q3 are grounded, a "3" terminal of the optical coupler U4 is connected with one end of the resistor R41, the other end of the resistor R41 is connected with a negative electrode of the diode D12, and a "4" terminal of the optical coupler U4 and a positive electrode of the diode D12 are grounded.

[0020] Further, the LED power supply circuit further comprises a capacitor CY1 and a capacitor CY2, one end of the capacitor CY1 is connected with an output end of the PFC circuit, the other end of the capacitor CY1 is grounded, and both ends of the capacitor CY2 are grounded.

[0021] Advantageous effects

[0022] The power supply device has the advantages that the power supply device is rationally designed in the power supply technology, the EMC filter circuit, the PFC circuit, the flyback circuit, the auxiliary power supply circuit, the PWM dimming circuit and the power output circuit are adopted, effective filtering can be realized without causing frequency flashing of the subsequent stage, PWM dimming can be realized, complete shutdown and stepless dimming between 0-100% can be realized, and the like.

[0023] The LED power supply circuit adopts two-stage mode to effectively reduce the stroboscopic of PWM power supply, and through the auxiliary power supply, complete optocoupling of the power supply can be realized, and 0-100% dimming without pole can be realized by cooperating with the regulation and control of PWM. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 It is a structure schematic view of the LED power supply circuit with PWM dimming and double-way output.

[0025] Fig. 2 It is a principle schematic view of the LED power supply circuit with PWM dimming and double-way output.

[0026] The number: 01, EMC filter circuit;02, PFC circuit;03, flyback circuit;04, power output circuit;05, auxiliary power supply circuit;06, PWM dimming circuit. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skilled in the art without creative labor belong to the protection scope of the utility model.

[0028] Referring to Figs. 1-2 The utility model provides a kind of LED power supply circuit with PWM dimming and double-way output, and the LED power supply circuit includes: EMC filter circuit 01, PFC circuit 02, flyback circuit 03, auxiliary power supply circuit 05, PWM dimming circuit 06 and power output circuit 04, the power input end of EMC filter circuit 01 is connected with external ac power supply, the output end of EMC filter circuit 01 is connected with the input end of PFC circuit 02, the output end of PFC circuit 02 is connected with the input end of flyback circuit 03 and the input end of auxiliary power supply circuit 05 respectively, the output end of flyback circuit 03 is connected with the input end of power output circuit 04, the output end of auxiliary power supply circuit 05 is connected with the input end of PWM dimming circuit 06, the signal end of flyback circuit 03 is connected with the signal end of PWM dimming circuit 06;

[0029] Wherein, PFC circuit 02 includes PFC input circuit and PFC control circuit, the input end of PFC input circuit is connected with the output end of EMC filter circuit 01, the output end of PFC input circuit is connected with the input end of PFC control circuit, the signal end of PFC control circuit is connected with the signal end of PFC input circuit.

[0030] Wherein, the flyback circuit 03 includes a flyback conversion circuit and a flyback control circuit, the input end of the flyback conversion circuit is connected with the output end of the PFC circuit 02, the input end of the flyback control circuit is connected with the output end of the flyback conversion circuit, the output end of the flyback conversion circuit is connected with the input end of the power output circuit 04, and the signal end of the flyback control circuit is connected with the signal end of the PWM dimming circuit 06;

[0031] Wherein, the auxiliary power circuit 05 includes an auxiliary circuit and an auxiliary control circuit, the input end of the auxiliary circuit is connected with the output end of the PFC circuit 02, the control end of the auxiliary circuit is connected with the control end of the auxiliary control circuit, and the output end of the auxiliary control circuit is connected with the input end of the PWM dimming circuit 06;

[0032] Wherein, specifically, the EMC filter circuit 01 includes a fuse F1, a thermistor NTC1, a voltage-dependent resistor RV1, a mutual inductor LF1, a resistor R19, a resistor R20, a resistor R22, a resistor R23, a capacitor CX1, a mutual inductor FL2 and a bridge DB1; the PFC input circuit includes an inductor L1, a resistor R61, a transformer T2, a resistor R12, a diode D2, a capacitor C2, a diode D3, an NMOS tube Q1, a capacitor C7, a diode D4, a resistor R13, a resistor R17, a resistor R62, a resistor R21, a resistor Rs0, a resistor Rs1, a resistor Rs2, a resistor R6, a resistor R16, a resistor R28, a capacitor C5 and a resistor Rs3; the PFC control circuit includes a chip U1, a diode D7, a capacitor C11, a capacitor C14, a capacitor C15, a resistor R33, a capacitor C9, a capacitor C13 and a resistor R29; the flyback conversion circuit includes a transformer T1, a capacitor C3, a capacitor EC1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R9, a resistor R10, a resistor R11, a capacitor C1, a diode D5-1 and a diode D5; the flyback control circuit includes a chip U2, a diode D6, a resistor R25, a resistor R26, a capacitor C10, a resistor R31, a resistor R34, a capacitor C16, a voltage stabilizing tube ZD1, a resistor R35, a resistor R27, a resistor R24, a diode D8, a resistor R63, a resistor R36, a resistor Rs4, a resistor Rs5, a resistor Rs6, a resistor Rs7, a resistor R30, an NMOS tube Q2, a capacitor C12, a resistor R64, a diode D15, a resistor R15, a resistor R14, a resistor R18 and a capacitor C8; the power output circuit 04 includes a voltage stabilizing tube D1, a capacitor C6, a resistor R5, a resistor R8, a capacitor CE1, a capacitor CE2, a resistor R7 and a mutual inductor LF3; the auxiliary circuit includes a chip U5, a resistor R40, a resistor R44, a resistor R50, a capacitor CE6, a capacitor C20, a resistor R57, a resistor R56, a resistor R37, a resistor R38, a capacitor C17, a resistor R43, a diode D11, a diode D13, a resistor R47, a resistor R55, a resistor R45, a transformer T3, a capacitor C18, a resistor R42, a capacitor CE3, an optical coupler U6, a resistor R46, a resistor R52, a resistor R48, a capacitor C19, a resistor R53, a voltage stabilizing tube U7, a resistor R59 and a resistor R60; the auxiliary control circuit includes an NPN tube Q4, a capacitor CE4, a voltage stabilizing tube ZD2, a resistor R51, a resistor R49, a PNP tube Q5, a resistor R54, a resistor R58, a capacitor CE5 and a diode D14; the PWM dimming circuit 06 includes an optical coupler U3, a resistor R32, a diode D9, an NPN tube Q3, a resistor R39, an optical coupler U4, a resistor R41 and a diode D12; the LED power supply circuit further includes a capacitor CY1 and a capacitor CY2;

[0033] Wherein, the fuse F1 of the EMC filter circuit 01 is connected with the live wire (AC-L) at one end, and connected with the one end of the pressure sensitive resistor RV1 and the "1" terminal of the mutual inductor LF1 at the other end, and connected with the one end of the thermistor NTC1 and the "4" terminal of the mutual inductor LF1 at the other end of the pressure sensitive resistor RV1, and connected with the zero wire (AC-N) at the other end of the thermistor NTC1, and connected with the one end of the parallel resistor R22 / R20, the one end of the capacitor CX1 and the "4" terminal of the mutual inductor FL2 at the "2" terminal of the mutual inductor LF1, and connected with the one end of the parallel resistor R23 / R19, the other end of the capacitor CX1 and the "1" terminal of the mutual inductor FL2 at the "3" terminal of the mutual inductor LF1, and connected with the other end of the parallel resistor R23 / R19 at the other end of the parallel resistor R22 / R20, and connected with the "2" terminal of the mutual inductor FL2 at the "3" terminal of the bridge DB1, and connected with the "3" terminal of the mutual inductor FL2 at the "4" terminal of the bridge DB1, and connected with the "1" terminal of the bridge DB1 at the ground, and connected with the one end of the inductor L1 of the PFC circuit 02 at the "4" terminal of the bridge DB1 of the EMC filter circuit 01;

[0034] Wherein, the inductor L1 of the PFC input circuit is connected with the "4" terminal of the bridge DB1 of the EMC filter circuit 01 at one end and the one end of the resistor R61, and connected with the one end of the capacitor C5, the positive electrode of the diode D2 and the "4" terminal of the transformer T2 at the other end of the inductor L1 and the other end of the resistor R61, and connected with the one end of the capacitor C2, the negative electrode of the diode D3, the one end of the resistor R6 and the one end of the resistor R40 of the auxiliary power supply circuit 05 at the negative electrode of the diode D2 and the one end of the capacitor C2, and connected with the other end of the capacitor C2, the positive electrode of the diode D3, the one end of the capacitor C7 and the drain electrode of the NMOS tube Q1 at the "2" terminal of the transformer T2, and connected with the other end of the capacitor C7 at the source electrode of the NMOS tube Q1 and the one end of the resistor R21 and the one end of the parallel resistor Rs0 / Rs1 / Rs2 / Rs3, and connected with the other end of the parallel resistor Rs0 / Rs1 / Rs2 / Rs3 at the ground, and connected with the "4" terminal of the chip U1 at the other end of the resistor R21, and connected with the resistor R16 and the resistor R28 in series at the other end of the resistor R6, and connected with the one end of the capacitor C13 at the other end of the resistor R28, and connected with the positive electrode of the diode D4, the one end of the resistor R62 and the one end of the resistor R13 at the gate electrode of the NMOS tube Q1, and connected with the negative electrode of the diode D4 and the one end of the resistor R17 at the other end of the resistor R13, and connected with the "7" terminal of the chip U1 at the other end of the resistor R17, and connected with the ground at the other end of the resistor R62, and connected with the ground at the other end of the capacitor C5, and connected with the ground at the "12" terminal of the transformer T2, and connected with the one end of the resistor R12 at the "11" terminal of the transformer T2, and connected with the "5" terminal of the chip U1 at the other end of the resistor R12;

[0035] Wherein, the chip U1 "1" terminal of the PFC control circuit connects one end of the resistance R29 and one end of the capacitor C13, the other end of the resistance R29 and the other end of the capacitor C13 are grounded, the chip U1 "2" terminal connects one end of the capacitor C15 and one end of the capacitor C14, the other end of the capacitor C15 connects one end of the resistance R33, the other end of the resistance R33 and the other end of the capacitor C14 are grounded, the chip U1 "4" terminal connects one end of the capacitor C9, the other end of the capacitor C9 and the chip U1 "6" terminal are grounded, the chip U1 "5" terminal connects the other end of the resistance R12 of the PFC input circuit, the chip U1 "7" terminal connects the other end of the resistance R17 of the PFC input circuit, the chip U1 "8" terminal connects the negative electrode of the diode D7 and one end of the capacitor C11, the positive electrode of the diode D7 connects the positive electrode (15V) of the external DC power supply, the other end of the capacitor C11 is grounded;

[0036] Wherein, the capacitor C3 of the flyback conversion circuit connects one end of the capacitor EC1, one end of the parallel resistance R1 / R2 / R3 / R4, one end of the capacitor C1 and the "3" terminal of the transformer T1, the other end of the capacitor C3 and the other end of the capacitor EC1 are grounded, the other end of the parallel resistance R1 / R2 / R3 / R4 connects the other end of the capacitor C1 and one end of the parallel resistance R9 / R10 / R11, the other end of the parallel resistance R9 / R10 / R11 connects the negative electrode of the diode D5-1 and the negative electrode of the diode D5, the positive electrode of the diode D5-1 and the positive electrode of the diode D5 connect the "1" terminal of the transformer T1 and the drain of the NMOS tube Q2;

[0037] Wherein, the chip U2 "1" terminal of the flyback control circuit is connected with the collector of NPN tube Q3 of PWM dimming circuit 06, the negative pole of voltage stabilizing tube ZD1 and one end of resistor R26, the positive pole of voltage stabilizing tube ZD1 is grounded, the other end of resistor R26 is connected with the chip U2 "8" terminal, the chip U2 "2" terminal is connected with one end of resistor R25, one end of resistor R31 and one end of resistor R34, the other end of resistor R34 is grounded, the other end of resistor R31 is connected with one end of capacitor C16 and the chip U2 "4" terminal, the other end of capacitor C16 is grounded, the other end of resistor R25 is connected with the negative pole of diode D6 and the chip U2 "8" terminal, the chip U2 "5" terminal is grounded, the chip U2 "6" terminal is connected with one end of parallel resistor R35 / R36 and one end of resistor R30, the other end of resistor R30 is connected with one end of parallel resistor Rs4 / Rs5 / Rs6 / Rs7, the other end of parallel resistor R35 / R36 and the other end of parallel resistor Rs4 / Rs5 / Rs6 / Rs7 are grounded in common, the chip U2 "7" terminal is connected with one end of resistor R27, the other end of resistor R27 is connected with the negative pole of diode D8 and one end of resistor R24, the positive pole of diode D8 and the other end of resistor R24 are connected with one end of resistor R63 and the gate of NMOS tube Q2 in common, the other end of resistor R63 is grounded, the source of NMOS tube Q2 is connected with the other end of resistor R30 and one end of capacitor C12, the drain of NMOS tube Q2 is connected with the other end of capacitor C12 and the "1" terminal of transformer T1 of flyback conversion circuit, the chip U2 "3" terminal is connected with one end of capacitor C8, one end of resistor R18, one end of resistor R14 and one end of resistor R15, the other end of capacitor C8, the other end of resistor R18 and the other end of resistor R14 are grounded in common, the other end of resistor R15 is connected with the "5" terminal of transformer T1 of flyback conversion circuit and one end of resistor R64, the other end of resistor R64 is connected with the positive pole of diode D15, the negative pole of diode D15 is connected with the DC power supply, the positive pole of diode D6 is connected with the DC power supply (15V);

[0038] Wherein, the positive pole of voltage stabilizing tube D1 of the power output circuit 04 is connected with one end of capacitor C6 and the "10" terminal and "11" terminal of transformer T1 of flyback circuit 03, the other end of capacitor C6 is connected with one end of parallel resistor R5 / R8, the other end of parallel resistor R5 / R8 is connected with the negative pole of diode D1, one end of parallel capacitor CE1 / CE2, one end of resistor R7 and the "3" terminal of mutual inductor LF3, the other end of parallel capacitor CE1 / CE2, the other end of resistor R7 and the "2" terminal of mutual inductor LF3 are grounded in common, the "4" terminal of mutual inductor LF3 is the output positive pole, the "1" terminal of mutual inductor LF3 is the output negative pole;

[0039] Wherein, the chip U5 "1" terminal connects the capacitor CE6 one end, the resistance R50 one end and the diode D13 negative pole, the capacitor CE6 other end is grounded, the chip U5 "2" terminal connects the capacitor C20 one end and the photoelectric coupling U6 "1" terminal, the capacitor C20 other end is grounded, the chip U5 "3" terminal connects the resistance R55 one end and the resistance R47 one end, the resistance R55 other end is grounded, the resistance R47 other end connects the transformer T3 "2" terminal and the resistance R45 one end, the resistance R45 other end connects the diode D13 positive pole, the transformer T3 "1" terminal is grounded, the chip U5 "4" terminal connects the parallel resistance R57 / R56 one end, the parallel resistance R57 / R56 other end is grounded, the chip U5 "5" terminal connects the chip U5 "6" terminal, the diode D11 positive pole and the transformer T3 "3" terminal, the diode D11 negative pole connects the resistance R43 one end, the resistance R43 other end connects the capacitor C17 one end, the resistance R38 one end and the resistance R37 one end, the capacitor C17 other end, the resistance R38 other end, the resistance R37 other end and the transformer T3 "5" terminal are connected to the resistance R40 one end and the output terminal of the PFC circuit 02, the resistance R40 other end connects the resistance R44 one end, the resistance R44 other end connects the resistance R50 other end, the chip U5 "8" terminal is grounded, the transformer "6" terminal and "7" terminal connect the diode D10 positive pole and the capacitor C18 one end, the capacitor C18 other end connects the resistance R42 one end, the resistance R42 other end connects the diode D10 negative pole, the resistance R42 other end, the resistance R46 one end, the resistance R48 one end, the capacitor CE3 one end and the DC power positive pole (+5V), the capacitor CE3 other end is grounded, the transformer T3 "9" terminal and "10" terminal are grounded, the resistance R46 other end connects the resistance R52 one end and the photoelectric coupling U6 "3" terminal, the photoelectric coupling U6 "2" terminal is grounded, the photoelectric coupling U6 "4" terminal connects the resistance R52 other end, the capacitor C19 one end and the stabilizing tube U7 negative pole, the stabilizing tube U7 positive pole is grounded, the stabilizing tube U7 third terminal connects the parallel resistance R59 / R60 one end, the resistance R53 one end and the resistance R48 other end, the resistance R53 other end connects the capacitor C19 other end, and the parallel resistance R59 / R60 other end is grounded.

[0040] Wherein, the capacitor CE4 of the auxiliary control circuit one end connects DC power supply (15V) and NPN tube Q4 emitter, NPN tube Q4 base connects the negative pole of ZD2 and the one end of R51, the positive pole of ZD2 is grounded, the other end of capacitor CE4 is grounded, the other end of R51 connects the one end of R49 and the collector of NPN tube Q4, the other end of R49 connects the emitter of PNP tube Q5, the base of PNP tube Q5 connects the one end of R54 and the one end of R58, the other end of R58 connects the input end of PWM light modulation circuit 06, the collector of PNP tube Q5 connects the other end of R54, the one end of capacitor CE5 and the negative pole of diode D14, the other end of capacitor CE5 is grounded, and the positive pole of diode D14 connects DC power supply (VDD);

[0041] Wherein, the light coupling U3 "1" terminal of the PWM light modulation circuit 06 connects the other end of R58 of auxiliary power supply circuit 05, the light coupling U3 "2" terminal is grounded, the light coupling U3 "3" terminal connects the one end of R32, the other end of R32 connects the negative pole of diode D9, the light coupling U3 "4" terminal and the positive pole of diode D9 are grounded in common, the light coupling U4 "1" terminal connects the one end of R39 and the base of NPN tube Q3, the other end of R39 connects DC power supply (15V), and the collector of NPN tube Q3 connects the "1" terminal of chip U2 of flyback circuit 03, the light coupling U4 "2" terminal and the emitter of NPN tube Q3 are grounded in common, the light coupling U4 "3" terminal connects the one end of R41, the other end of R41 connects the negative pole of diode D12, and the light coupling U4 "4" terminal and the positive pole of diode D12 are grounded in common.

[0042] Wherein, the one end of capacitor CY1 connects the output end of PFC circuit 02, and the other end of capacitor CY1 is grounded, and the two ends of capacitor CY2 are grounded.

[0043] The specific embodiment of the utility model discloses: power supply front end is 90-264VAC input, then after fuse F1, pressure-sensitive resistance RV1, carry out two-stage filtering and thermistor NTC1, can effectively reduce the inrush current of input, in order to realize high PF value, a π type filter circuit is in the rear end of bridge type DB1, reduces the interference generated by PFC circuit;

[0044] The control circuit of the PFC adopts a chip U1 (model: BP2628 of Jingfeng Mingyuan) as a master control, the chip U1 detects the zero-crossing state of the inductor current through the ZCD pin; when the GATE is off and the freewheeling diode freewheeling ends, the load winding voltage begins to drop, and the ZCD pin voltage also drops; when the ZCD voltage is lower than the demagnetization detection threshold, the chip U1 detects the demagnetization signal and starts the next conduction period; the ZCD pin is also used to detect the input voltage, for THD compensation and conduction time control; when the GATE is high, the auxiliary winding voltage becomes negative, and the negative current through the ZCD current limiting resistor flows out from the ZCD; the chip U1 detects the input voltage by detecting the current, for THD compensation; at the same time, there is also an auxiliary power output, which adopts a chip U5 (model OB2365E), the main function of this line is to provide auxiliary power for the main circuit, and is used to power the following main control board, at the same time, the control signal can control the corresponding power supply, so that the main circuit is completely turned off, and no power consumption and current are generated; the following is a chip U2 (model BP3179D) used as the master control of the flyback power supply, the PWM signal of the secondary side reaches the PWM pin of the chip U2 through the optocoupler isolation and the triode, so that the function of dimming can be realized.

[0045] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A dual-output LED power supply circuit with PWM dimming, characterized in that, The LED power supply circuit includes: an EMC filter circuit, a PFC circuit, a flyback circuit, an auxiliary power supply circuit, a PWM dimming circuit, and a power output circuit. The power input terminal of the EMC filter circuit is connected to an external AC power supply. The output terminal of the EMC filter circuit is connected to the input terminal of the PFC circuit. The output terminal of the PFC circuit is connected to the input terminals of the flyback circuit and the auxiliary power supply circuit, respectively. The output terminal of the flyback circuit is connected to the input terminal of the power output circuit. The output terminal of the auxiliary power supply circuit is connected to the input terminal of the PWM dimming circuit. The signal terminal of the flyback circuit is connected to the signal terminal of the PWM dimming circuit. The PFC circuit includes a PFC input circuit and a PFC control circuit. The input terminal of the PFC input circuit is connected to the output terminal of the EMC filter circuit, the output terminal of the PFC input circuit is connected to the input terminal of the PFC control circuit, and the signal terminal of the PFC control circuit is connected to the signal terminal of the PFC input circuit. The PFC control circuit includes chip U1, diode D7, capacitors C11, C14, and C15, resistors R33, C9, C13, and R29. Terminal "1" of chip U1 is connected to one end of resistor R29 and one end of capacitor C13. The other end of resistor R29 and the other end of capacitor C13 are grounded. Terminal "2" of chip U1 is connected to one end of capacitor C15 and one end of capacitor C14. The other end of capacitor C15 is connected to one end of resistor R33. The other end of resistor R33... One end of the chip is grounded along with the other end of capacitor C14. Terminal U1"4 of the chip is connected to one end of capacitor C9. The other end of capacitor C9 and terminal U1"6 of the chip are grounded together. Terminal U1"5 of the chip is connected to the output terminal of the PFC input circuit. Terminal U1"7 of the chip is connected to the signal terminal of the PFC input circuit. Terminal U1"8 of the chip is connected to the negative terminal of diode D7 and one end of capacitor C11. The positive terminal of diode D7 is connected to the positive terminal of the external DC power supply. The other end of capacitor C11 is grounded.

2. The LED power supply circuit with dual output and PWM dimming according to claim 1, characterized in that, The PFC input circuit includes inductor L1, resistor R61, transformer T2, resistor R12, diode D2, capacitor C2, diode D3, NMOS transistor Q1, capacitor C7, diode D4, resistors R13, R17, R62, R21, Rs0, Rs1, Rs2, R6, R16, R28, capacitor C5, and resistor Rs3. One end of inductor L1 and one end of resistor R61 are connected to the E... At the output of the MC filter circuit, the other end of inductor L1 and the other end of resistor R61 are connected to one end of capacitor C5, the positive terminal of diode D2, and the "4" terminal of transformer T2. The negative terminal of diode D2 is connected to one end of capacitor C2, the negative terminal of diode D3, one end of resistor R6, the input terminal of the flyback circuit, and the input terminal of the auxiliary power supply circuit. The other end of capacitor C2 and the positive terminal of diode D3 are connected to the "2" terminal of transformer T2, one end of capacitor C7, and the drain of NMOS transistor Q1. The other end of capacitor C7 is connected to the source of NMOS transistor Q1, one end of resistor R21, and one end of parallel resistors Rs0 / Rs1 / Rs2 / Rs3. The other end of parallel resistors Rs0 / Rs1 / Rs2 / Rs3 is grounded. The other end of resistor R21 is connected to terminal U1"4 of chip. The other end of resistor R6 is connected in series with resistors R16 and R28. The other end of resistor R28 is connected to one end of capacitor C13. The gate of NMOS transistor Q1 is connected to the anode of diode D4, one end of resistor R62, and one end of resistor R13. The other end of resistor R13 is connected to the cathode of diode D4 and one end of resistor R17. The other end of resistor R17 is connected to terminal U1"7 of chip. The other end of resistor R62 is grounded. The other end of capacitor C5 is grounded. Terminal T2"12 of transformer is grounded. Terminal T2"11 of transformer is connected to one end of resistor R12. The other end of resistor R12 is connected to terminal U1"5 of chip.

3. The LED power supply circuit with dual output and PWM dimming according to claim 1, characterized in that, The EMC filter circuit includes a fuse F1, a thermistor NTC1, a varistor RV1, a mutual inductor LF1, resistors R19, R20, R22, and R23, a capacitor CX1, a mutual inductor FL2, and a bridge circuit DB1. One end of the fuse F1 is connected to the live wire, and the other end of the fuse F1 is connected to one end of the varistor RV1 and the "1" terminal of the mutual inductor LF1. The other end of the varistor RV1 is connected to one end of the thermistor NTC1 and the "4" terminal of the mutual inductor LF1. The other end of the thermistor NTC1 is connected to the neutral wire, and the "2" terminal of the mutual inductor LF1 is connected to the parallel resistor R2. One end of 2 / R20, one end of capacitor CX1, and the FL2"4 terminal of mutual inductor are connected. The FL2"3 terminal of mutual inductor is connected to one end of parallel resistor R23 / R19, the other end of capacitor CX1, and the FL2"1 terminal of mutual inductor. The other end of parallel resistor R23 / R19 is connected to the other end of parallel resistor R22 / R20. The FL2"3 terminal of mutual inductor is connected to the DB1"2 terminal of bridge circuit. The FL2"2 terminal of mutual inductor is connected to the DB1"3 terminal of bridge circuit. The DB1"1 terminal of bridge circuit is grounded. The DB1"4 terminal of bridge circuit is connected to the input terminal of the PFC circuit.

4. The LED power supply circuit with dual output and PWM dimming according to claim 1, characterized in that, The flyback circuit includes a flyback converter circuit and a flyback control circuit. The input terminal of the flyback converter circuit is connected to the output terminal of the PFC circuit. The input terminal of the flyback control circuit is connected to the output terminal of the flyback converter circuit. The output terminal of the flyback converter circuit is connected to the input terminal of the power output circuit. The signal terminal of the flyback control circuit is connected to the signal terminal of the PWM dimming circuit.

5. The LED power supply circuit with dual output and PWM dimming according to claim 4, characterized in that, The flyback control circuit includes chip U2, diode D6, resistors R25 and R26, capacitor C10, resistors R31 and R34, capacitor C16, Zener diode ZD1, resistors R35, R27 and R24, diode D8, resistors R63 and R36, resistors Rs4, Rs5, Rs6, Rs7, and R30, NMOS transistor Q2, capacitor C12, resistor R64, diode D15, resistors R15 and R14, resistor R18, and capacitor C8. The "1" terminal of chip U2 is connected to the signal of the PWM dimming circuit. The circuit consists of the cathode of Zener diode ZD1 and one end of resistor R26. The anode of Zener diode ZD1 is grounded. The other end of resistor R26 is connected to terminal U2"8 of chip U2. Terminal U2"2 of chip U2 is connected to one end of resistor R25, one end of resistor R31, and one end of resistor R34. The other end of resistor R34 is grounded. The other end of resistor R31 is connected to one end of capacitor C16 and terminal U2"4 of chip U2. The other end of capacitor C16 is grounded. The other end of resistor R25 is connected to the cathode of diode D6 and terminal U2"8 of chip U2. Terminal U2"5 of chip U2 is grounded. Terminal U2"6 of chip U2 is connected to terminal U2"6 of chip U2. The terminal "7" of the chip U2 is connected to one end of parallel resistors R35 / R36 and one end of resistor R30. The other end of resistor R30 is connected to one end of parallel resistors Rs4 / Rs5 / Rs6 / Rs7. The other ends of parallel resistors R35 / R36 and Rs4 / Rs5 / Rs6 / Rs7 are grounded together. The terminal "7" of the chip U2 is connected to one end of resistor R27. The other end of resistor R27 is connected to the cathode of diode D8 and one end of resistor R24. The anode of diode D8 and the other end of resistor R24 ​​are connected to one end of resistor R63 and the gate of NMOS transistor Q2. The other end of resistor R63 is grounded. NMOS transistor Q2... The source terminal is connected to the other end of resistor R30 and one end of capacitor C12. The drain terminal of NMOS transistor Q2 is connected to the other end of capacitor C12 and the flyback converter circuit. The "3" terminal of chip U2 is connected to one end of capacitor C8, one end of resistor R18, one end of resistor R14, and one end of resistor R15. The other ends of capacitor C8, resistor R18, and resistor R14 are grounded together. The other end of resistor R15 is connected to the output terminal of the flyback converter circuit and one end of resistor R64. The other end of resistor R64 is connected to the anode of diode D15. The cathode of diode D15 is connected to the DC power supply. The anode of diode D6 is connected to the DC power supply.

6. The LED power supply circuit with dual output and PWM dimming according to claim 5, characterized in that, The flyback converter circuit includes a transformer T1, a capacitor C3, a capacitor EC1, resistors R1, R2, R3, R4, R9, R10, R11, a capacitor C1, a diode D5-1, and a diode D5. One end of capacitor C3 is connected to one end of capacitor EC1, one end of parallel resistors R1 / R2 / R3 / R4, one end of capacitor C1, and the "3" terminal of transformer T1. The other end of capacitor C3 and the other end of capacitor EC1 are grounded together. The other end of parallel resistors R1 / R2 / R3 / R4 is connected to the other end of capacitor C1 and one end of parallel resistors R9 / R10 / R11. The other end of parallel resistors R9 / R10 / R11 is connected to the negative terminals of diodes D5-1 and D5. The positive terminals of diodes D5-1 and D5 are connected to the "1" terminal of transformer T1 and the drain of NMOS transistor Q2.

7. The LED power supply circuit with dual output and PWM dimming according to claim 1, characterized in that, The power output circuit includes a Zener diode D1, a capacitor C6, a resistor R5, a resistor R8, a capacitor CE1, a capacitor CE2, a resistor R7, and a mutual inductor LF3. The positive terminal of the Zener diode D1 is connected to one end of the capacitor C6 and the output terminal of the flyback circuit. The other end of the capacitor C6 is connected to one end of the parallel resistor R5 / R8. The other end of the parallel resistor R5 / R8 is connected to the negative terminal of the diode D1, one end of the parallel capacitor CE1 / CE2, one end of the resistor R7, and the "3" terminal of the mutual inductor LF3. The other ends of the parallel capacitor CE1 / CE2, the other end of the resistor R7, and the "2" terminal of the mutual inductor LF3 are grounded. The "4" terminal of the mutual inductor LF3 serves as the positive output terminal, and the "1" terminal of the mutual inductor LF3 serves as the negative output terminal.

8. The LED power supply circuit with dual output and PWM dimming according to claim 1, characterized in that, The auxiliary power supply circuit includes an auxiliary circuit and an auxiliary control circuit. The input terminal of the auxiliary circuit is connected to the output terminal of the PFC circuit, the control terminal of the auxiliary circuit is connected to the control terminal of the auxiliary control circuit, and the output terminal of the auxiliary control circuit is connected to the input terminal of the PWM dimming circuit.

9. A dual-output LED power supply circuit with PWM dimming according to claim 8, characterized in that, The auxiliary circuit includes chip U5, resistors R40, R44, and R50, capacitors CE6 and C20, resistors R57, R56, R37, and R38, capacitor C17, resistor R43, diodes D11 and D13, resistors R47 and R55, transformer T3, capacitor C18, resistor R42, capacitor CE3, optocoupler U6, resistors R46, R52, and R48, capacitor C19, resistor R53, Zener diode U7, resistor R59, and resistor R60. Terminal "1" of chip U5 is connected to one end of capacitor CE6, one end of resistor R50, and the negative terminal of diode D13. The other end of capacitor CE6 is grounded. Terminal U5"2 of chip U5"2 is connected to one end of capacitor C20 and terminal U6"1 of optocoupler U6. The other end of capacitor C20 is grounded. Terminal U5"3 of chip U5"2 is connected to one end of resistor R55 and one end of resistor R47. The other end of resistor R55 is grounded. The other end of resistor R47 is connected to terminal T3"2 of transformer U5"2 and one end of resistor R45. The other end of resistor R45 is connected to the anode of diode D13. Terminal T3"1 of transformer U5"2 is grounded. Terminal U5"4 of chip U5"2 is connected to one end of parallel resistor R57 / R56. The other end of parallel resistor R57 / R56 is grounded. Terminal U5"5 of chip U5"2 is connected to terminal U5"6 of chip U5"2, the anode of diode D11, and terminal T3"3 of transformer U5"2. The cathode of diode D11 is connected to terminal U5"6 of chip U5"2, the anode of diode D11, and terminal T3"3 of transformer U5"2. Connect one end of resistor R43. The other end of resistor R43 is connected to one end of capacitor C17, one end of resistor R38, and one end of resistor R37. The other ends of capacitor C17, resistor R38, and resistor R37, along with the "5" terminal of transformer T3, are connected to one end of resistor R40 and the output terminal of the PFC circuit. The other end of resistor R40 is connected to one end of resistor R44. The other end of resistor R44 is connected to the other end of resistor R50. The "8" terminal of chip U5 is grounded. The "6" and "7" terminals of the transformer are connected to the anode of diode D10 and one end of capacitor C18. The other end of capacitor C18 is connected to one end of resistor R42. The other end of resistor R42 is connected to the cathode of diode D10 and the other end of resistor R42. One end of resistor R46, one end of resistor R48, one end of capacitor CE3, and the positive terminal of DC power supply are connected. The other end of capacitor CE3 is grounded. The "9" and "10" terminals of transformer T3 are grounded together. The other end of resistor R46 is connected to one end of resistor R52 and the "3" terminal of optocoupler U6. The "2" terminal of optocoupler U6 is grounded. The "4" terminal of optocoupler U6 is connected to the other end of resistor R52, one end of capacitor C19, and the negative terminal of Zener diode U7. The positive terminal of Zener diode U7 is grounded. The third terminal of Zener diode U7 is connected to one end of parallel resistor R59 / R60, one end of resistor R53, and the other end of resistor R48. The other end of resistor R53 is connected to the other end of capacitor C19. The other end of parallel resistor R59 / R60 is grounded.

10. A dual-output LED power supply circuit with PWM dimming according to claim 9, characterized in that, The auxiliary control circuit includes an NPN transistor Q4, a capacitor CE4, a Zener diode ZD2, resistors R51 and R49, a PNP transistor Q5, resistors R54 and R58, a capacitor CE5, and a diode D14. One end of capacitor CE4 is connected to a DC power supply and the emitter of NPN transistor Q4. The base of NPN transistor Q4 is connected to the negative terminal of Zener diode ZD2 and one end of resistor R51. The positive terminal of Zener diode ZD2 is grounded. The other end of capacitor CE4 is grounded. The other end of resistor R51 is connected to one end of resistor R49 and the collector of NPN transistor Q4. The other end of resistor R49 is connected to the emitter of PNP transistor Q5. The base of PNP transistor Q5 is connected to one end of resistor R54 and one end of resistor R58. The other end of resistor R58 is connected to the input terminal of the PWM dimming circuit. The collector of PNP transistor Q5 is connected to the other end of resistor R54, one end of capacitor CE5, and the negative terminal of diode D14. The other end of capacitor CE5 is grounded. The positive terminal of diode D14 is connected to a DC power supply.

Images